The present invention relates to photoresists. More particularly it relates to novel monomers in photoresists that are polymerizable in the presence of oxygen.
Monomers whose polymerization is insensitive to air are uncommon, since most monomers react by free-radical mechanisms, which are strongly inhibited by oxygen. However, air insensitive monomers are very desirable for use in photoresists, which are polymerized under conditions where the diffusion of oxygen is particularly facile.
U.S. Pat. No. 3,899,338 issued to J. M. Lewis, discloses the use of an N-vinylcarbazole as the photopolymerizable monomer in a photoresist. These monomers are polymerizable in the presence of oxygen and give good photospeed. However, appending useful functional groups to N-vinylcarbazoles is difficult, for example, appending an alkyl group to the number 3 position of N-vinylcarbozole renders it unstable and necessitates its immediate use under anhydrous conditions.